Biology subjects

de Alwis, R.

Publications and source records attributed to de Alwis, R..

3 recordsLinked to original sources

bioRxiv2025

Organ-specific isolation of hepatocyte extracellular vesicles from human plasma enables tissue-resolved proteomic and miRNA profiling

Tissue-specific resolution remains a key limitation in liquid biopsy to achieve the highest accuracy for precision medicine. To address this limitation, we developed NEXPLOR (Novel EXtracellular vesicle PopuLation and Omics Revealer), a magnetic bead-based platform enabling selective immuno-isolation of tissue-derived EVs. Focusing on hepatocyte-derived EVs (h-EVs), we demonstrate NEXPLORs specificity and sensitivity in capturing rare EV subpopulations directly from human plasma. Using in silico tissue marker discovery, we identified and validated a TOP4 capture antibody panel (ASGR1, ASGR2, TFR2, SLCO1B1) for h-EV isolation through an ultrasensitive orthogonal method (O-NEXOS). Applied to liver disease using clinical plasma samples, NEXPLOR enabled deeper and more reproducible proteomic profiling compared to matched bulk EVs, revealing liver-specific and disease-relevant pathways, including ferroptosis, HIF-1 signaling, and central carbon metabolism in cancer. Moreover, small RNA sequencing uncovered a reduced but highly informative set of miRNAs, including miR-124-3p and miR-23b-3p, differentially expressed in hepatocellular carcinoma (HCC) compared to cirrhosis, and undetectable in bulk EVs. These molecular signatures suggest disease state based on real-time hepatocyte biology. Our findings establish NEXPLOR as a robust platform for tissue-specific EV capture, enabling tissue-resolved, multi-omic biomarker discovery. This opens new frontiers in early disease detection, longitudinal monitoring, and AI-powered biomarker discovery for precision medicine.

molecular biology↗

bioRxiv2019

Phenotype and functionality of follicular helper T cells in patients with acute dengue infection

BackgroundThe association of functionality and phenotype of follicular helper T cells (Tfh) with dengue virus (DENV) specific antibody responses and clinical disease severity is has not been well studied.\n\nMethodology/Principal findingsWe investigated the phenotype and functionality of Tfhs in adult patients (DF = 18, DHF = 22) with acute dengue of varying severity using multiparametric flowcytometry. We determined if the properties of Tfhs were correlated with viraemia, disease severity, plasmablast responses and DENV-specific serum antibody responses. We further evaluated the changes in neutralizing antibodies (Neut50) with viraemia and clinical disease severity in a different cohort of patients with acute secondary DENV1 (DF=12, DHF=10) and DENV2 infection (DF=8, DHF=9).\n\nTfhs (especially those producing IL-21 and co-expressing PD-1 and ICOS) were found to be significantly expanded (p<0.0001) and highly activated in patients with DHF compared to those with DF. The frequency of Tfh cells significantly correlated with DENV-specific IgG, NS1-specific antibodies and Neut50 antibody titres, which were also significantly higher in patients with DHF. Although the Neut50 titres increased during the course of acute secondary DENV infection, they showed differences based on serotype. For instance, the Neut50 titres were significantly higher during the latter part of illness in patients with DF compared DHF in DENV1 infection, while in DENV2, patients with DHF had significantly higher titres. The viral loads during early illness did not correlate with the subsequent rise in the Neut50 antibody titres during time point of illness.\n\nConclusions/SignificanceThe expansion of Tfhs is associated with DHF and DENV-specific IgG, NS1-specific and neutralising antibodies. Neut50 titres did not associate with disease severity or viraemia at the point of first presentation during the febrile phase, but later titres do show differential association with severity in patients with DENV1 compared to DENV2.\n\nAuthor summaryFollicular helper T cells (Tfh cells) are a subset of T cells which are important in activation of germinal centre T cells and induction of long-lasting virus specific antibodies. The association of the functional status and phenotype of Tfh cells in relation to dengue virus (DENV) specific antibodies, clinical disease severity and the degree of viraemia in patients with acute dengue has not been extensively studied. Here we show that the Tfh cells are significantly expanded in patients with severe clinical disease and associate with levels of serum DENV envelop specific IgG, NS1-specific antibodies and neutralising antibodies (Neu50). Although DENV Neu50 antibody titres are thought to associate with protection, the Neut50 antibody titres were similar in patients who proceeded to develop mild or severe clinical disease and also the increase in their titres showed significant variation based on infecting DENV serotype and clinical disease severity. Therefore, although Tfh cells are expanded in patients with more severe forms of disease, and associate with DENV-specific antibody responses, they do not appear to have a protective role.

immunology↗

bioRxiv2017

Quantifying antimicrobial access and practices for paediatric diarrheal disease in an urban community setting in Southeast Asia

Antimicrobial-resistant infections are increasing across Asia. Aiming to evaluate antimicrobial access and practices in Ho Chi Minh City (HCMC) of Vietnam, we mapped pharmacy locations and used a simulated client method to calculate antimicrobial sales for paediatric diarrheal disease. We additionally evaluated healthcare choices for parents and caregivers when their children experienced diarrhoea. District 8 (population 396,175) of HCMC had 301 pharmacies (one for every 1,316 people), with a density of 15.8 pharmacies/km2. A wide range of different treatments (n=57) were sold for paediatric diarrheal disease, with 8% (3/37) and 22% (8/37) of the sampled pharmacies selling antimicrobials for watery and mucoid diarrhoea, respectively. Despite the apparent abundance of pharmacies, the majority of caregivers chose to take their child to a specialized hospital, with 81% (319/396) and 88% (347/396) of responders selecting this as their first, second, or third choice for watery and mucoid diarrhoea, respectively. Lastly, by combining denominators derived from caregiver interviews and diarrheal incidence figures, we calculated that 16% (2,359/14,427) of watery or mucoid diarrhoea episodes of the District 8 population aged 1 to <5 years would receive an antimicrobial for diarrhoea annually, but antimicrobial prescribing was almost ten times greater in hospitals than in the community. Our novel mixed-methods approach found that, whilst antimicrobials are commonly available for paediatric diarrhoea in the community of HCMC, usage is greater in hospitals. The observed non-standardized approach to diarrheal treatments is indicative of poor recommendations. We advocate better guidelines, training and dissemination of information regarding antimicrobials and their use in this location.

epidemiology↗